Microfabricated lenses are a key-enabling technology for Datacom and Telecom applications, especially to implement co-packaged optics (CPO) for optical transceivers based on photonic integrated circuits (PIC). The manufacturing of such microlenses needs to be compatible with high-volume production, without sacrificing the optical quality and performances. For most applications, the output of an astigmatic beam from a laser diode needs to be collimated in the x- and y-directions: this correction cannot be performed by a rotationally-symmetric lens. A compact approach can be adopted by means of only one elliptical microlens, which has a different focal length in both directions. Here, we propose an analytical model, which can be applied for designing and fabricating elliptical microlenses by means of the reflow process, which is fully based on the optical description of the lens, in terms of RoC and conic constants. The model is demonstrated through a wafer-level fabrication of such lenses.
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